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Application of Surface Treatment on Hand Tools
Vraspírová, Eva ; Klakurková, Lenka (referee) ; Doležal, Pavel (advisor)
Bachelor's thesis deals with problems of materials, which are used to production of hand tools and implements. The theoretical part is focused on tool steels, their mechanical and technological characteristics and to their heat processing. Below there are well-arranged and described surface modification, which are applied to materials nowadays. The next part is focused on modern technology of surface modification, which are applied to hand tools. The research is mainly focused on technology of production of bits by company Wera Werk Ltd, which is deal with production and distribution of hand tightening tools, such as screwdrivers, angular keys, plug keys, bits and torque tools. Attention is also paid to technology of surface modification, e.g. based on zinc phosphate, nickel, nickel-gold and nickel-diamond-gold, used for these tools and to problems of painting. To elements interaction study light microscopy, the hardness measurement by Vickers and Brinell and scanning electron microscopy equipped by energy dispersive microanalyses.
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An effective cutting tool for shearing of spring wires
Smékal, Jan ; Sliwková, Petra (referee) ; Píška, Miroslav (advisor)
The goal of this master thesis was to propose modification of a cutting tool for shearing of spring wires with focus on improving its lifetime. An analysis of cutting process was made which confirmed low lifetime of lower cutting tool – average lifetime of cutting tool is 3 734 pieces. Suggestions were made in the thesis such as change of current technology, change of material of cutting tool or local change of cutting edge of the tool. Three changes were designed – insert from sintered carbide, hardfacing welding of the cutting edge and insert from high-speed steel. Testing of sintered carbide inserts ČSN ISO 513 HC – P80 and ČSN ISO 513 HC – P60 showed that sintered carbides are too brittle for cutting spring wires. Five hardfacing welding materials (HS6-5-2, HS2-9-2, X37CrMoW5-1, Stellite6 and Stellite12) have been tested. Material X37CrMoW5-1 had the best lifetime results with lifetime of 2 463 pieces. This material was further tested and average lifetime achieved was 2 021 pieces. However, there was decrease of hardness in a heat-affected zone. The last change of cutting edge was an insert from high-speed steels HS12-1-4 and HS10-4-3-10. These inserts were broken prematurely at the soldered joint and both high-speed steels exhibited cracks due to high material hardness (60 and 65 HRC), very low toughness at extremal loading.
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Application of Surface Treatment on Hand Tools
Vraspírová, Eva ; Klakurková, Lenka (referee) ; Doležal, Pavel (advisor)
Bachelor's thesis deals with problems of materials, which are used to production of hand tools and implements. The theoretical part is focused on tool steels, their mechanical and technological characteristics and to their heat processing. Below there are well-arranged and described surface modification, which are applied to materials nowadays. The next part is focused on modern technology of surface modification, which are applied to hand tools. The research is mainly focused on technology of production of bits by company Wera Werk Ltd, which is deal with production and distribution of hand tightening tools, such as screwdrivers, angular keys, plug keys, bits and torque tools. Attention is also paid to technology of surface modification, e.g. based on zinc phosphate, nickel, nickel-gold and nickel-diamond-gold, used for these tools and to problems of painting. To elements interaction study light microscopy, the hardness measurement by Vickers and Brinell and scanning electron microscopy equipped by energy dispersive microanalyses.
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